Energy transfer between Ce3+ and Sm3+ in Zn2GeO4 phosphor with the native defects for light-emitting diodes

A series of Ce3+, Sm3+-doped Zn2GeO4 phosphors are prepared by the solid-state reaction. A blue photoluminescence (PL) of Zn2GeO4 is observed as the recombination of the electrons trapped on VO• and Zni• with holes trapped on VGe and VZn′. The energy transfer process between Ce3+ and Sm3+ is confirmed by the PL spectra and decay curves, and the emission colors can be adjusted from blue to orange–red. Furthermore, we verify unambiguously that the energy transfer from Ce3+ to Sm3+ occurs. Besides, Ce3+ ions can act as a bridge, possibly promoting the energy transfer from the Zn2GeO4 host matrix to Sm3+ ions.